Thousands of gallons of fuel seeped about 20 feet into the ground near where a tractor-trailer crashed east of Angelus Oaks, but authorities on Wednesday said the fuel did not reach a nearby creek that feeds into the Santa Ana River.

Crews from a private contractor worked through Tuesday night into Wednesday near Highway 38, continuing to excavate soil tainted by the spill. The mountain highway is expected to remain closed today.

“We have no idea when this road will be reopened,” Caltrans spokeswoman Terri Kasinga said. “It’s still undetermined.”

Workers brought heavy equipment up the mountain Wednesday to begin digging into the soil below the highway to determine how much damage the fuel spill caused.

Caltrans officials have said that as much as 150 feet of highway may have to be replaced.

San Bernardino County and U.S. Forest Service firefighters stood by during the cleanup, putting out several small fires ignited by backhoes striking rocks.

“We’re trying to use as little water as possible because you don’t want it to sink further down into the soil,” said county fire spokeswoman Tracey Martinez.

Firefighters also had to spray foam on top of the soil because heavy fumes emanated from the ground.

A tanker truck hauling 8,200 gallons of fuel overturned and ruptured on the highway east of Angelus Oaks about 10 p.m. Monday.

Officials initially estimated that workers recovered more than 3,000 gallons that spilled, but that number has since dropped to 2,200. The California Highway Patrol said 6,000 gallons of fuel soaked into the soil in a catch basin below the highway.

The spill prompted the evacuation of nearby Camp Cedar Falls due to fears the spill could spark a brush fire.

Water agencies in Redlands and Highland shut down treatment plant operations until they could determine if water in the Santa Ana River had been contaminated.

Robert Deloach, interim general manager of the Highland-based East Valley Water District, is hoping to receive lab results from water samples today.

“If it ends up that we have trace amounts of it, then we’re not going to take any chances,” he said.

Chris Diggs, assistant utilities director for Redlands, said personnel plan to continue testing water in the Santa Ana River for the next several days.

Both agencies receive water from sources other than the Santa Ana River, so residents won’t be affected by the temporary plant closures, officials said.